Color filter and liquid crystal display device using it, and manufacturing method thereof

ABSTRACT

An object of the invention is to provide a color filter and a liquid crystal display device using it, which can acquire uniform color purity within a pixel. A color filter for coloring the first light ray L 1  having a unidirectional optical path and the second light ray L 2  having a bidirectional optical path for each pixel. This filter comprises: a step-forming layer of optically transmissive material, which can be supported by a base layer  20 , and which is patterned for a pixel to form at least one recess-shaped portion having a bottom face  3   b  of a predetermined shape corresponding to an area wherein the first light ray L 1  is caused to be transmitted and a wall face  3   w  of a predetermined height; and a coloring layer  1 C deposited on the step-forming layer  30  and the recess-shaped portion for coloring the first and second light rays.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a color filter. The presentinvention also relates to a liquid crystal display device employing acolor filter.

[0003] In particular, the present invention relates to a color filterwhich handles a first light ray and a second light ray. The first lightray has such a unidirectional optical path that the light ray incidentfrom one principal plane side of the filter passes through the filteronly once to be colored and is guided to the other principal plane sideof the filter. The second light ray has such a bi-directional opticalpath that the light ray incident from the other principal plane side ofthe color filter passes through the filter to be colored and the passedlight ray is reflected by an optical reflective element or the likedisposed in the one principal plane side to enter the filter again andpass to be colored, and comes back to the other principle plane side.The invention also relates to a method of manufacturing the colorfilter. The invention further relates to a liquid crystal display deviceusing such a color filter, and to a method of manufacturing the liquidcrystal display device.

[0004] 2. Description of Related Art

[0005] A liquid crystal display device, what is called the transflectivetype liquid crystal display device, becomes in full practical use,wherein external light incident from the front side is reflected to beguided to the front side while being provided with an optical modulationaccording to the image to be displayed, and incident light from the backlight system on the rear side is passed to the same front side whilebeing likewise provided with the optical modulation according to theimage to be displayed. This type of liquid crystal display deviceeffectively performs displays of image based on the external light(ambient light) mainly when the operating environment is bright(reflective mode) and based on emission light from the back light systemmainly when it is dark (transmissive mode).

[0006] Such a type of liquid crystal display device is disclosed in aprior art document, “Development of Advanced TFT with Good Legibilityunder Any Intensity of Ambient Light” by M. Kubo et al., IDW' 99,Proceedings of The Sixth International Display Workshops, AMD3-4, page183-186, Dec. 1, 1999, sponsored by ITE and SID. In this device, eachpixel electrode is divided into a reflection area and a transmissionarea. The reflection area is a reflection electrode part formed fromaluminium with which an acrylic resin with a rough surface is covered,and the transmission area is a transparent electrode part formed fromITO (Indium Tin Oxide) with a flat surface. The transmission area issituated in the center of a rectangular pixel area and has asubstantially similar rectangular figure like the pixel area, whereasthe reflection area is a part of the pixel area other than therectangular transmission area and has a form of surrounding thetransmission area. By virtue of the pixel configuration etc, thelegibility is improved.

SUMMARY OF THE INVENTION

[0007] However, in the prior art liquid crystal display device, thetransmission area and the reflection area are different in color purityof the displayed color although these areas are in the same pixel area.It is supposed that this problem results from the color filter in theprior art in which the light from the back-light system and the externallight whose optical paths are different from each other are colored inmuch the same fashion. As a result, the quality of the displayed colorsis deteriorated over the display area.

[0008] In view of the above-mentioned points, it is an object of thepresent invention to provide a color filter and a liquid crystal displaydevice using the color filter, which can show more uniform color puritywithin a pixel.

[0009] It is another object of the present invention to provide a colorfilter and a liquid crystal display device using the color filter, whichcan satisfactorily reproduce chromaticity over a display area.

[0010] It is a further object of the present invention to providemethods of manufacturing the color filter and the liquid crystal displaydevice.

[0011] In order to achieve the above-described objects, a color filteraccording to one aspect of the present invention is a color filter forcoloring a first light ray having a unidirectional optical path and asecond light ray having a bidirectional optical path for each pixel,comprising: a first coloring portion for coloring the first light rayand a second coloring portion for coloring the second light ray, thefirst and second coloring portions differeing in thickness, or is, infurther development, a color filter for coloring a first light rayhaving a unidirectional optical path and a second light ray having abidirectional optical path for each pixel, comprising: a step-forminglayer of optically transmissive material, which can be supported by abase layer, and which is patterned for a pixel to form at least onerecess-shaped portion having a bottom face of a predetermined shapecorresponding to an area wherein the first light ray is caused to betransmitted and a wall face of a predetermined height; and a coloringlayer deposited on the step-forming layer and the recess-shaped portionfor coloring the first and second light rays.

[0012] According to this aspect, a thickness of the coloring layer'sportion (the first coloring portion) corresponding to the bottom facemay be greater than that of the remainder (the second coloring portion)of the coloring layer. This leads to the following effects andadvantages. That is, on the one hand, the first light ray, which followsa unidirectional optical path and which thus has only one opportunity tobe colored, can undergo a relatively high degree of coloring effect, andthe other hand, the second light ray, which follows a bi-directionaloptical path and which thus has two opportunities to be colored, canundergo a relatively low degree of coloring effect. Accordingly, it ispossible to reproduce the corresponding colors in more uniform colorpurity within a pixel for the first and second light rays, therebyimproving the quality of a color-displaying over an entire area of thedisplay screen.

[0013] In this aspect, the coloring layer's portion corresponding to thebottom face may have a thickness substantially two times larger thanthat of the remainder of the coloring layer. This construction allows alight ray incident on the color filter to be much uniformly colored.

[0014] In addition, the step-forming layer may be colorless andtransparent. This manner makes it possible to form a step (or differenceof level) in a surface on which the coloring layer is to be depositedwithout affecting the coloring effects caused by the coloring layer.

[0015] Moreover, the step-forming layer may be formed from a syntheticresin. This allows the step-forming layer to be formed from ordinarymaterials.

[0016] Also in the aspect, preferably the color filter may furthercomprise a flattening layer of optically transmissive material which isdeposited on at least an area corresponding to the bottom face on thecoloring layer. Thus, a recess of the coloring layer possibly formed bythe bottom face and the step is filled with the optically-transmissivematerial for the flattening layer, and as a result an entire surface ofthe color filter is flattened. Accordingly, planes of incidence of lightare uniformalized over the color filter's surface to suppress anunexpected light leakage resulting from the recess, thereby greatlycontributing to improvement of the optical performance for the coloringeffect. In addition, even in the case where a further layer is providedon the color filter, the further layer never comes into direct contactwith the coloring layer because of existence of the flattening layer.For instance, contamination of liquid crystal layer can be avoided.Furthermore, the flattened surface of the color filter can preventalignment disorder (irregularity) of the alignment layer and the liquidcrystal layer disposed on and above the color filter, respectively.

[0017] The flattening layer in this manner may be colorless andtransparent. This leads not to affect the coloring performance of thecoloring layer while keeping the above-described effects and advantages.

[0018] Furthermore, the flattening layer may be formed from a syntheticresin. This achieves an advantage of being able to add the flatteninglayer based on an ordinary and inexpensive material.

[0019] Also in this aspect, the first coloring portion or the bottomface may have at least in part a rounded shape on a plan view. And thefirst coloring portion or the bottom face may have substantially acircle shape on a plan view. Alternatively, the first coloring portionor the bottom face may have substantially a shape of polygon that isenclosed with 5 or more line segments on a plan view. Thus, therecess-shaped portion of the step-forming layer is formed, instead ofsimple rectangle shape, in such a shape that represents a polygon havinggreater interior angles or includes a curving line having a large radiusof curvature as an outline thereof. This is advantageous with regard toforming the desired pattern accurately.

[0020] The step-forming layer may include an optically transmissive basematerial and multiple particles of optically transmissive materialhaving a refractive index different from a refractive index of the basematerial and being scatteringly mixed into the base material, and thebase material and particles may consist of synthetic resins. This mannerhas advantages that the step-forming layer has an optically diffusing(scattering) ability and therefore only the second light ray can beselectively diffused. Accordingly, the manner reduces the need formaking the other components to have an optical diffusing ability for thesecond light ray, and can exert the suitable diffusion effect for thesecond light ray in the refection mode, independent of diffusion for thefirst light ray.

[0021] In order to achieve the above-described objects, a liquid crystaldisplay device according to another aspect of the present inventionemploys any color filter according to the above-mentioned aspect.

[0022] This aspect may be characterized in that: the color filter isprovided to one substrate of the liquid crystal display device; theother substrate is provided with a pixel electrode comprising atransmissive electrode part for making the first light ray to betransmitted therethrough and a reflective electrode part for making thesecond light ray to be reflected therefrom; and the first coloringportion or an area of the bottom face in the color filter is alignedwith the transmissive electrode part and the other area in the colorfilter is aligned with the reflective electrode part.

[0023] The above-described liquid crystal display device is able torealize uniform color purity within each pixel, thereby obtaining highquality color images for display.

[0024] Furthermore, in order to achieve the above-described objects, amethod of manufacturing a color filter according to a further aspect ofthe present invention is a method of manufacturing a color filter forcoloring a first light ray having a unidirectional optical path and asecond light ray having a bidirectional optical path for each pixel,comprising the steps of: depositing an optically transmissive materialon a base layer; patterning the deposited layer of opticallytransmissive material to form a step-forming layer wherein at least onerecess-shaped portion is formed for a pixel, the recess-shaped portionhaving a bottom face of a predetermined shape corresponding to an areawherein the first light ray is caused to be transmitted and a wall faceof a predetermined height; and depositing a material for coloring thefirst and second light rays on the step-forming layer and therecess-shaped portion so as to form a coloring layer.

[0025] Accordingly, the color filter, which can make thepreviously-described effects and advantages, can be manufactured in arelatively simple manner.

[0026] In this aspect, the method may further comprise the step ofdepositing an optically transmissive material on at least an areacorresponding to the bottom face on the coloring layer so as to form aflattening layer. Accordingly, it is possible to manufacture the colorfilter capable of acquiring the above-described advantages relating tothe flattening layer.

[0027] Moreover, in order to achieve the above-described objects, amethod of manufacturing a liquid crystal display device according to yetfurther aspect of the present invention is a method of manufacturing aliquid crystal display device, comprising the steps included in themanufacturing method for a color filter as mentioned above, wherein thecolor filter is provided to one substrate of the liquid crystal displaydevice and the other substrate is provided with a pixel electrodecomprising a transmissive electrode part for making the first light rayto be transmitted therethrough and a reflective electrode part formaking the second light ray to be reflected therefrom, the displaydevice manufacturing method further comprising the step of aligning anarea of the bottom face in the color filter with the transmissiveelectrode part and aligning the other area in the color filter with thereflective electrode part.

[0028] According to this method, it is possible to give on-targetdirections to manufacture of a liquid crystal display device which canmuch satisfactorily use the advantages of the above-described colorfilters.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a general plan view of a color filter employed in aliquid crystal display device according to the first embodiment of thepresent invention;

[0030]FIG. 2 is a general and enlarged plan view of sub-regions of acolor filter for a pixel of FIG. 1;

[0031]FIG. 3 is a general cross sectional view of a color filterincorporated within a liquid crystal panel, taken along the line III-IIIof FIG. 2;

[0032]FIG. 4 is a general cross sectional view of a color filteraccording to the second embodiment of the present invention;

[0033]FIG. 5 is a general cross sectional view of a color filteraccording to the third embodiment of the present invention; and

[0034]FIG. 6 is a general cross sectional view of a color filteraccording to the fourth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0035] Now the above-mentioned aspects and other aspects according tothe present invention will be described in more detail with reference tothe accompanying drawings.

[0036] [Embodiment 1]

[0037]FIG. 1 illustrates a general plan view of a color filter 1employed in a liquid crystal display device of a first embodimentaccording to the present invention.

[0038] The color filter 1 is partitioned into longitudinal coloringareas each of which extends in a vertical direction of a display screen,and which have coloring matters of red (R), green (G) and blue (B),respectively. These longitudinal coloring areas are cyclically arrangedin order of R, G and B in a horizontal direction on the display screen.One longitudinal coloring areas may be further divided in a verticaldirection, and each of the divisional portions corresponds to a pixel.The divisional portion will be referred to as a pixel area part 10hereinafter. It is noted that although the longitudinal coloring areasare partitioned in a vertical direction by dashed lines as shown in FIG.1, the pixel area parts 10 (the pixel area parts 10 vertically aligned)of one longitudinal coloring area are neither isolated materially norphysically in the embodiment. The dashed lines just indicate boundariesof pixels.

[0039]FIG. 2 illustrates a general enlarged plan view of one pixel areapart 10, and FIG. 3 illustrates a cross sectional view of a color filterincorporated into a liquid crystal display panel 100, taken along theline III-III of FIG. 2. It should be noted that FIG. 3 illustrates abasic construction of a liquid crystal display panel, and therefore, inorder to simplify the description, minor layers, films and structuresthereof are omitted.

[0040] The pixel area part 10 is partitioned into a first region 10 tfor a transmitted light ray L1 as a first light ray, a second region 10r for a reflected light ray L2 as a second light ray. The first region10 t and the second region 10 r respectively correspond to and arealigned with a transmissive region (transmissive electrode part) 8 t anda reflective region (reflective electrode part) 8 r, the transmissiveand reflective regions being formed in a pixel electrode 80 provided ona substrate 70 which is disposed facing the first and second regions viaa liquid crystal layer LC.

[0041] The first region 10 t is formed substantially shaped like acircle whose center is positioned in the center of the pixel area, andthe second region 10 r is in a form that is a part except the region 10t and surrounds the region 10 t. Therefore, it is assumed in theembodiment that electrode parts formed in the pixel electrode 80 arealso shaped substantially equal to those of the regions 10 t and 10 r ina plan view, respectively.

[0042] As shown in FIG. 3, the pixel area part 10 comprises: atransparent resin layer 30 as a step forming layer formed on a frontside transparent substrate 20 of the liquid crystal display panel 100and formed inside the panel; and a coloring layer 1C formed on andcovering the transparent substrate 20 and the transparent resin layer30.

[0043] The transparent resin layer 30 is patterned to have a shape ofthe second region 10 r, shown in the plan view. In more detail, thetransparent resin layer 30 can be supported by the substrate 20 and ispatterned within a pixel (area) to have a recess-shaped portioncomprising a predetermined shape of bottom surface 3 b corresponding toa region for allowing a transmitted light ray L1 to pass therethroughand a wall surface 3 w having a predetermined height to thereby form astep on a surface on which the coloring layer 1C is to be deposited.

[0044] In the embodiment, only a part of the transparent resin materialcorresponding to the first region 10 t is removed so that an opening (orwindow) for the transparent substrate 20 is formed in an area of thepart. The coloring layer 1C has the first region 10 t on the opening andthe second region 10 r on the remainder part thereof, in more detail, ona portion of the transparent resin layer 30 having been patterned.Therefore, as could be clearly understood by referring to the figure, apart (first coloring portion) of the coloring layer 1C corresponding tothe first region 10 t is formed thicker than a part (second coloringportion) of the coloring layer 1C corresponding to the second region 10r.

[0045] It is preferable that the part of the coloring layer 1Ccorresponding to the first region 10 t is made approximately two timesthe part of the coloring layer 1C corresponding to the second region 10r for the following reasons.

[0046] For example, after a light ray L1 from a backlight system passesthrough a transparent electrode part 8 t and a liquid crystal layer LC,it is colored by a portion of the coloring layer 1C corresponding to thefirst region 10 t while being guided to an exterior on the front faceside of the panel. On the other hand, an external light ray L2 from thefront face side of the panel passes though the transparent substrate 20and the transparent resin layer 30, and is once colored by a portion ofthe coloring layer 1C corresponding to the second region 10 r and thenreaches the reflective electrode part 8 r through the liquid crystallayer LC while it is colored again through the portion of the coloringlayer 1C corresponding to the second region 10 r after it is reflectedthe reflective electrode part 8 r and returns to the portion.Thereafter, the external (colored) light ray passes through thetransparent resin layer 30 and the transparent substrate 20 to bedirected to the exterior of the front face side of the panel.

[0047] As described above, since the first part of the coloring layer inthe first region 10 t is thicker than the second part of the coloringlayer in the second region 10 r, it causes the transmitted light ray L1to be subjected to relatively great coloring effect even if thetransmitted light ray is transmitted through the first part only onetime. On the other hand, since the coloring layer portion of the secondregion 10 r is thinner than coloring layer portion of the first regionlot, it can not exert the same degree of coloring effect as the firstregion 10 t exerts. However, since the reflected light ray L2 istransmitted two times through the coloring layer portion of the secondregion 10 r, the light ray L2 is subjected to double coloring effect.Therefore, it is sufficed to have such a thickness of the coloring layerportion of the second region 10 r that the reflected light ray L2 canundergo a sufficient degree of coloring effect when the light ray L2 istransmitted two times through the coloring layer portion of the secondregion 10 r. Actually, the coloring layer portion of the second region10 r should be made thinner than the coloring layer portion of the firstregion 10 t in consideration of a balance between coloring effectsexerted by the coloring layer portions of the first and second regions10 t and 10 r.

[0048] Thus, the transmitted light ray L1 and the reflected light ray L2appearing in the outside of the front side of the panel are uniformlycolored so that good color reproduction characteristics are obtainedwithin a pixel and over an entire area of the display screen.

[0049] [Embodiment 2]

[0050] A second embodiment that is more advanced than theabove-described embodiment is shown in FIG. 4.

[0051] A pixel area part 10A of a color filter in FIG. 4 comprises alayer 30A as a step-forming layer which includes an opticallytransmissive base material (or matrix material) 3S and a large number ofoptically transmissive particles 3P having a refractive index differentfrom that of the base material and being scatteredly added to the basematerial. The other structural features are the same as those of FIG. 3.

[0052] The layer 30A has a function of diffusing (or scattering) a lightray incident thereon and passing therethrough. This function is mainlybased on a difference between the refractive indexes of the basematerial 3S and the particles 3P and also depends on parameters such asshapes, sizes, density and/or distributional condition of the particlesin the base material. In order to prevent unfavorable coloring caused byinteraction, the particles 3P are preferably dispersed randomly withinthe base material, and shapes and sizes of the particles are preferablyirregular to some extent. Both the base material 3S and the particles 3Pmay be made of a synthetic resin.

[0053] Accordingly, the reflected light ray L2 will be diffused by thestep-forming layer 30A, whereby the following advantages are obtained.

[0054] That is, the transmitted light ray L1 is usually a light ray froma backlight and usually enters the color filter as a light ray havingbeen diffused by a light-guide plate or the like, whereas the reflectedlight ray L2 is usually an external light ray except any light rays froma front-light and the external light ray enters the color filter with itbeing not diffused. In the above-mentioned prior art reference, asurface of the reflective electrode part of the pixel electrode isroughened so as to diffuse the reflected light under consideration for aviewing angle Characteristic or the like. However, the embodiment canperform further diffusion in the step-forming layer 30A without relyingon the roughening of the prior art or in addition to the diffusion basedon the roughening for the purpose of complement.

[0055] In addition, since the step-forming layer 30A can selectivelydiffuse the reflected light ray L2, it is possible to get a diffusioncharacteristic suitable for the reflected light ray L2 by optimizing theabove-described parameters or the like. For instance, in the case ofproviding a diffusion film extending over an entire display area of theouter face of the display panel, the light ray L1, which has alreadybeen diffused through the above-described light guide plate or the like,resultantly becomes excessively diffused, so that an unfavorablesituation would occur in that transmittance and contrast are lowered ina transmissive mode. The embodiment can also address such an unfavorablesituation.

[0056] It should be noted that a resin layer having such diffusionperformance and the construction thereof are described in more detail inJapanese Patent Application Laid-open No. 2000-330106, which is utilizedfor guidance to realize them.

[0057] [Embodiment 3]

[0058] In the first and second embodiments, there was described theexamples where the surface of the coloring layer 1C is sufficientlyflattened. If the surface of the coloring layer 1C is flat, planes ofincidence for light rays on the surface is uniformly flattened within apixel. This leads to advantages in respect of optical performance forcoloring effect or the other respects.

[0059] However, actually in order to make the surface of the coloringlayer 1C to be flat, an entire thickness of the coloring layer 1C has tobe considerably large or has to be formed using a special material forthe coloring layer 1C. The first region 10 t forms a recess-shapedportion defined by a pattern of the transparent resin layer 30 and astep (or difference in level) is made on a face on which the coloringlayer 1C is deposited so as to correspond to the first region 10 t. So,if the coloring layer 1C is deposited on the face and then treated forfinishing (cured or the like) through a conventional process, thecoloring layer portion of the first region 10 t becomes concave as shownin FIG. 5.

[0060] To prevent the coloring layer from being formed to have such aconcave shape, the coloring layer is to be deposited sufficiently thickso as not to become concave in the finishing. However, underconsideration for getting the desired coloring effect of the colorfilter, the coloring layer 1C should not be formed much thicker only forthe purpose of preventing the coloring layer from becoming recessed.Furthermore, although a material capable of preventing the coloringlayer 1C from becoming concave in the first region 10 t can also beemployed for the coloring layer to overcome that, it leads to anunfavorable situation where a special material has to be prepared onlyfor the usual coloring layer 1C.

[0061] For these reasons, a second embodiment is intended to have thesteps of forming a coloring layer 1C′ having a desired film thicknessbut keeping a concave shape as shown in FIG. 5 and then curing it, andsubsequently applying a transparent resin to the coloring layer 1C′ toform an overcoat layer 1 p as a flattening layer. With thisconstruction, the recess of the coloring layer 1C′ in the first region10 t is filled with the transparent resin material. As a result, asurface of a pixel area part 10′ of the color filter or an entiresurface of the color filter is flattened as shown in FIG. 5. As theadded overcoat layer 1 p is optically transparent, it never affects thecoloring performance of the coloring layer.

[0062] Accordingly, the provision of the overcoat layer 1 p makes thesurface of the color filter to be flattened thereby to make the planesof incidence to be more uniform, which reduces an unexpected lightleakage possibly caused by the concave shape, thereby greatlycontributing to improvement of the optical performance for the coloringeffect.

[0063] Furthermore, even in the case where the other layer such as analignment layer (not shown) is formed on the color filter, the coloringlayer 1C′ never comes in direct contact with the other layer, so thatthe liquid crystal layer can be advantageously free from contamination,for example. Moreover, since the surface of the color filter is madeflattened, fluctuations of alignment in the alignment layer and liquidcrystal layer LC respectively disposed on and above the color filter canbe prevented.

[0064] In the above-mentioned embodiments, there were examples in whichthe pixel area part 10 corresponding to a pixel in the color filter ispartitioned into two regions, i.e., the circular first region 10 t fortransmission and the second region 10 r for reflection surrounding theregion lot. However, the present invention is not necessarily limited tothose examples. Such sub-regions may be three or more regions and thedivisional areas may be designed in any shape, any layout and anynumber.

[0065] Fundamentally, the transmissive region and the reflective regionof the color filter correspond to regions (in the cited embodiments, thetransmissive part and the reflective part formed in the pixel electrode,respectively) that are assigned to the first light ray and the secondlight ray, respectively, the light rays being handled by the displaydevice, and the geometric shape, disposition and the number of thetransmissive and reflective regions are designed to coincide with thoseof the assigned regions. Therefore, instead of the circular first region10 t and the second region 10 r surrounding the first region as shown inthe foregoing embodiments, the first region may be shaped like arectangle, generally shaped like a rectangle with four corners beingrounded (including an ellipse) or shaped like a polygon enclosed withfive or more line segments. Note that the recess-shaped portion of thestep-forming layer 30, 30A may be preferably configured to have a shapehaving at least a part of an outline of a polygon with greater interiorangles or a curved line with a greater radius of curvature. Suchgeometric configuration is advantageous for forming the desired patternaccurately. This point becomes more important as the display device isintended to have a screen composed of finer pixels.

[0066] Needless to say, further various modifications may be made in theinvention. For example, the pixel area part may be not necessarilyformed in cross stripes pattern as shown in FIG. 1. Furthermore, therecess-shaped portion formed in the transparent resin layer 30, 30A is aperfect opening or aperture that causes the support layer for the layer30, 30A i.e. the substrate 20 to be exposed and the bottom surface ofthe recess-shaped portion is the surface of the substrate 20. However,as shown in FIG. 6, a step-forming layer 30′ having a wall surface 3 w′around the recess-shaped portion may be formed based on a lower parttransparent resin layer 30 b that has a bottom face formed thinner fromthe same material as that of the step-forming layer 30′. Additionally,although the foregoing embodiments employ the color filter formeddirectly on the substrate 20, some foundational layer may be insertedbetween the substrate 20 and the color filter. That is, the presentinvention is directed to a color filter capable of being supported by abase layer implying such foundational layer and substrate.

[0067] Moreover, instead of the transparent resin layer of completecolorlessness and transparence, a resin layer capable of coloring may beemployed for some purposes. Additionally, although the foregoingembodiments employ a color filter for three primary colors, R, G and Bso as to display full-color images, the present invention is applicableto a color filter for a single color used to display monochrome images.Furthermore, additional elements such as a black matrix, which arerequired at wish depending on a display system, have not been explainedin the foregoing embodiments, but it will be apparent that such elementsare not excluded in the present invention.

[0068] The preferred embodiments described herein are thereforeillustrative and not restrictive, the scope of the invention beingindicated by the appended claims, and all variations which come withinthe meaning of the claims are intended to be embraced therein.

1. A color filter for coloring a first light ray having a unidirectionaloptical path and a second light ray having a bidirectional optical pathfor each pixel, comprising: a first coloring portion for coloring thefirst light ray and a second coloring portion for coloring the secondlight ray, the first and second coloring portions differeing inthickness.
 2. A color filter as defined in claim 1, CHARACTERIZED inthat a thickness of the first coloring portion is greater than that ofthe second coloring portion.
 3. A color filter as defined in claim 1,CHARACTERIZED in that the first coloring portion has a thicknesssubstantially two times larger than that of the second coloring portion.4. A color filter as defined in any one of claims 1-3, CHARACTERIZED inthat the first coloring portion has at least in part a rounded shape ona plan view.
 5. A color filter as defined in claim 4, CHARACTERIZED inthat first coloring portion has substantially a circle shape orsubstantially a shape of polygon that is enclosed with 5 or more linesegments on a plan view.
 6. A color filter for coloring a first lightray having a unidirectional optical path and a second light ray having abidirectional optical path for each pixel, comprising: a step-forminglayer of optically transmissive material, which can be supported by abase layer, and which is patterned for a pixel to form at least onerecess-shaped portion having a bottom face of a predetermined shapecorresponding to an area wherein the first light ray is caused to betransmitted and a wall face of a predetermined height; and a coloringlayer deposited on the step-forming layer and the recess-shaped portionfor coloring the first and second light rays.
 7. A color filter asdefined in claim 6, CHARACTERIZED in that a thickness of the coloringlayer's portion corresponding to the bottom face is greater than that ofthe remainder of the coloring layer.
 8. A color filter as defined inclaim 6, CHARACTERIZED in that the coloring layer's portioncorresponding to the bottom face has a thickness substantially two timeslarger than that of the remainder of the coloring layer.
 9. A colorfilter as defined in claim 6, 7 or 8, CHARACTERIZED in that thestep-forming layer is colorless and transparent.
 10. A color filter asdefined in any one of claims 6-9, CHARACTERIZED in that the step-forminglayer is formed from a synthetic resin.
 11. A color filter as defined inany one of claims 6-10, CHARACTERIZED in that the color filter furthercomprises a flattening layer of optically transmissive material which isdeposited on at least an area corresponding to the bottom face on thecoloring layer.
 12. A color filter as defined in claim 11, CHARACTERIZEDin that the flattening layer is colorless and transparent.
 13. A colorfilter as defined in claim 11 or 12, CHARACTERIZED in that theflattening layer is formed from a synthetic resin.
 14. A color filter asdefined in any one of claims 6-13, CHARACTERIZED in that the bottom facehas at least in part a rounded shape on a plan view.
 15. A color filteras defined in any one of claims 6-14, CHARACTERIZED in that the bottomface has substantially a circle shape or substantially a shape ofpolygon that is enclosed with 5 or more line segments on a plan view.16. A color filter as defined in any one of claims 6-15, CHARACTERIZEDin that the step-forming layer includes an optically transmissive basematerial and multiple particles of optically transmissive materialhaving a refractive index different from a refractive index of the basematerial and being scatteringly mixed into the base material.
 17. Acolor filter as defined in claims 16, CHARACTERIZED in that the basematerial and particles consist of synthetic resins.
 18. A liquid crystaldisplay device using a color filter as defined in any one of claims1-17.
 19. A liquid crystal display device as defined in claim 18,CHARACTERIZED in that: the color filter is provided to one substrate ofthe liquid crystal display device; the other substrate is provided witha pixel electrode comprising a transmissive electrode part for makingthe first light ray to be transmitted therethrough and a reflectiveelectrode part for making the second light ray to be reflectedtherefrom; and an area of the bottom face in the color filter is alignedwith the transmissive electrode part and the other area in the colorfilter is aligned with the reflective electrode part.
 20. A method ofmanufacturing a color filter for coloring a first light ray having aunidirectional optical path and a second light ray having abidirectional optical path for each pixel, comprising the steps of:depositing an optically transmissive material on a base layer;patterning the deposited layer of optically transmissive material toform a step-forming layer wherein at least one recess-shaped portion isformed for a pixel, the recess-shaped portion having a bottom face of apredetermined shape corresponding to an area wherein the first light rayis caused to be transmitted and a wall face of a predetermined height;and depositing a material for coloring the first and second light rayson the step-forming layer and the recess-shaped portion so as to form acoloring layer.
 21. A method as defined in claim 16, CHARACTERIZED inthat the method further comprises the step of depositing an opticallytransmissive material on at least an area corresponding to the bottomface on the coloring layer so as to form a flattening layer.
 22. Amethod of manufacturing a liquid crystal display device, comprising thesteps included in a method as defined in claim 16 or 17, wherein thecolor filter is provided to one substrate of the liquid crystal displaydevice and the other substrate is provided with a pixel electrodecomprising a transmissive electrode part for making the first light rayto be transmitted therethrough and a reflective electrode part formaking the second light ray to be reflected therefrom, the displaydevice manufacturing method further comprising the step of aligning anarea of the bottom face in the color filter with the transmissiveelectrode part and aligning the other area in the color filter with thereflective electrode part.